A water emergency switch is an electronic sensor fitted into your HVAC system. Its role is to shut off the entire AC system automatically when it detects a drainage clog. This device is commonly known as AC flat switch, air conditioning wet switch, and safety switch.
When your AC is shut off, it stops dehumidifying the air. Hence, no more moisture will be converted to additional water that will continue to clog up your HVAC drainage system.
HVAC water emergency switches vary in design and mechanism, but its primary work is to stop the air conditioner from operating when a clog or overflow is detected. Certain levels of water in the drainage pans activate the switch mechanism. The switch device will then alert the AC unit, triggering it to stop working.